Reusable thermal pack and flow retardant gel for use therein

ABSTRACT

A thermal pack for heating or cooling portions of a body and a flow retardant gel for use therein. The thermal pack includes a gel pad and a pressure chamber. The gel includes a fibrous material disposed therein to essentially prevent flow and increase heat capacity.

This application is a continuation of application Ser. No. 07/869,541,filed Apr. 15, 1992, abandoned, which is a division of application Ser.No. 794,726, filed Nov. 15, 1991, abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a thermal pack and gel for use therein, andmore particularly to a thermal pack having a gel pack and a separatepressure chamber which can be inflated and deflated and a flow retardantgel for use therein for use on sore or injured body portions.

Ice packs and heat packs have proved their therapeutic usefulness fortreatment of aches, pains, sprains and the like and have taken on newsignificance in the field of medicine, particularly sports relatedmedicine. It has been well recognized that heat, cold and pressure aloneor in various combinations may be helpful aids to therapy and first aid.Conventional heat packs or cold packs require the use of straps, tape orwrap to hold them in place, making them difficult and often messy touse. Additionally, it is difficult to surround a limb and to supplyuniform contact over the entire area.

Various methods of providing heat and cold to injuries have been used.Most common is the ice pack which uses a conventional polymer bag withcrushed ice or ice cubes enclosed therein, or a fluid that isendothermic and which is activated one time by breaking an encapsulatedpouch. A more advanced example of an ice pack is a plastic bag or pouchcontaining an extremely viscous flowable gel material of water, glycoland clay. Common disadvantages of conventional gels are that theyinclude fast flow rates, or high motility, so that when the pack is usedthe gel will flow or migrate rapidly away from all pressure points,thereby thinning out over the area to which the gel is most needed andthickening at the periphery where it is least useful. Additionally, thegel may migrate rapidly downward in response to gravity from areas ofthe pad which are in a vertical position. This diminishes theeffectiveness of the pad in application of heat or cold.

Previously, the only means of providing a combination of heat andpressure or cold and pressure has been to use the conventional heat orcold packs in conjunction with tape or elastic bandages or otherwrapping material. These methods make it extremely difficult to supplyeven pressure and even heating or cooling of the desired surface.

SUMMARY OF THE INVENTION

The present invention provides a reusable thermal pack which includes aninner pad or pads which encapsulate a gel or other semi-solid medium,and an external inflatable and deflatable pressure chamber, or chambers.Reusable thermal packs of this type can be made to conform to a pillowor pad-like configuration, a tube configuration or any number of variousconfigurations. Additionally, a means for circulating liquid through achamber or chambers situated adjacent to or embedded within the gel pador pads can be incorporated to provide for continuous heating or coolingof the gel or semi-solid medium.

Additionally, a flow retardant gel having a slow or negligible flowrate, or low motility rate compared with conventional gels and a higherheat capacity compared with conventional gels is provided. Such a flowretardant gel includes a fibrous, flaked or shredded material includedin the gel.

The resultant reusable thermal pack provides a means for applying heat,cold or pressure, or any combination of these therapies in conjunctionwith one another to a body portion. The pack can be easily designed toconform to body parts without the need for tape, bandages or otherwrappings to hold it in place during use. Additionally, the pack assuresmore uniform contact between the hot or cold pack with the affectedarea. Also, the flow retardant gel provides for a uniform heating orcooling system which does not flow away from pressure points or flow dueto the influence of gravity when in a vertical or elevated position.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in greater detail in the following detaileddescription of examples embodying the best mode of the invention, takenin conjunction with the drawing figures, in which:

FIG. 1 is a cross-sectional view of one embodiment of the presentinvention,

FIG. 2 is a perspective view of an embodiment of the present inventionincorporating a pocket for the insertion of either the gel pad therein,

FIG. 3 is a cross-sectional view of an additional embodiment of theinvention in the form of a tube,

FIG. 4 is a cross-sectional view of yet another embodiment of theinvention incorporating a means on one side for circulating liquid tocontinuously heat or cool the gel of the present invention, and

FIG. 5 is a cross-sectional view of still another embodiment of theinvention which includes an internal means for circulating liquid tocontinuously heat or cool the gel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of a thermal pack according to the invention is showngenerally at 10 in FIG. 1. The thermal pack 10 includes two basicportions, a gel bag or pad 12 and a pressure bag or chamber 14 disposedcontiguous to and coextensive with the gel pad 12. A conventional valve16 is disposed in the pressure chamber 14 for inflation and deflation ofthe pressure chamber 14. The gel pad 12 has an outer shell made of aflexible membrane material such as polyvinyl chloride or any othersuitable material. The pressure chamber 14 has an outer shell made of asimilar flexible membrane material. In the form illustrated the gel pad12 and the pressure chamber 14 share a common wall 18. The gel pad 12and pressure chamber 14 may be conformed into any shape or size and thegel pad 12 may be similar or dissimilar to the shape of pressure chamber14. Additionally, the gel pad 12 may include openings and/or void areasor shapes. Both the gel pad 12 and the pressure chamber 14 may be asingle or multi-chambered unit.

A gel 20 is disposed within the gel pad 12 and is a semi-rigid colloidaldispersion of a solid with a liquid which retains heat or cold dependingon the temperatures to which the pack 10 has been subjected. Whilesuitable flow retardant gel 20 will be discussed herein, the thermalpack 10 is adapted for use with any other suitable gel material.

A fastening means or closure, such as a hook and loop fastener 22, maybe included on or in conjunction with the thermal pad to aid inpositioning or holding the device in place during use. Such fasteningmeans or closure can include but is not limited to buckles, clasps,clips, snaps, buttons and hook and loop fasteners.

As shown in FIG. 2, the gel pad 12 may be separate from the pressurechamber 14 (rather than sharing a common wall 18 as in FIG. 1), and thethermal pack 10 may include one or more pockets or envelopes 24 intowhich the gel pad 12 or pressure chamber 14 may be inserted. It ispreferred that if a pocket 24 is employed, the pocket 24 be sealed orinclude means for sealing so that the encapsulated gel pad or pressurechamber does not inadvertently fall out.

In use, the pressure bag chamber 14 is inflated via the valve 16 andremains at a constant internal pressure in use until the pressure isadjusted. If the pressure chamber 14 is a multi-chambered unit, pressuremay vary between the individual chambers. Additionally, the pressurechamber 14 provides external insulation for the gel pad 12 therebyallowing the gel pad 12 to retain heat or cold for longer periods oftime. This arrangement allows for the uniform cooling or heating of anaffected area while applying both pressure and heat or cold therapy. Thepack 10 may be of any size and shape such as a pillow, cushion, wedge,collar, mask, bolster, mat, mattress, sling or cradle.

Another embodiment of the invention is shown in FIG. 3. This embodimentillustrates a tubular pack 10' that includes a gel chamber or pad 12'and an external pressure chamber 14'. The external pressure chamber 14'includes a valve 16 to allow for inflation and deflation of the pressurechamber 14'. The pressure chamber 14' is disposed adjacent the gel pad12' and both are conformed into a tubular shape. This tubular shapeallows an affected limb or body part to be inserted therethrough andsurrounded for treatment. Alternatively, a non-tubular form which iswrapped around the body part to conform into a generally tubular shapecan be used. The non-tubular form can be shaped into a tube and be heldin such form with a zipper, hook and loop fastener, snaps or buttons, orsimply by friction.

When the external pressure chamber 14' is filled with air via the valve16, an even amount of pressure is exerted on the inner gel pad 12' andprovides for an even cooling or heating therapy and even pressuretherapy. The inflated pressure chamber 14' also holds the thermal pack10' in place on a limb and can allow for more mobility of a patientduring treatment. The pressure chamber 14' also provides insulation forthe gel pad 12' thereby allowing the gel pad 12' to retain heat or coldfor longer periods without reheating or refreezing. The shape of formshown in FIG. 3 is tubular. However, several variations of this tubularshape may be made, such as a cuff, sleeve, cap, boot or vest.

As shown in FIGS. 4 and 5, a fluid heat exchanger 26 can be included inthe thermal pack 10'' or 10'''. Such a fluid heat exchanger 26 includesliquid tubes in serpentine or maze configurations situated adjacent toor embedded within the gel pad 12 to increase, decrease or vary thetemperature of the gel 20 in the gel pad 12. A liquid, not shown, can becirculated through the tubes to provide for temperature variations inthe gel 20. Such a pack provides for a more even distribution oftemperature because the gel pad 12 can conform to the shape of a bodypart. The gel pad 12 provides a semi-insulative barrier between the heatexchanger 26 and the body part, and more evenly distributes the heat orcold of the circulated fluid. Thus, the temperature of the circulatingfluid can be changed easily and quickly, yet the gel 20 of the gel pad12 will change gradually. In this manner, the user will be less likelyto experience discomfort or injury due to exposure to extremetemperatures.

The flow retardant gel 20 of the present invention will now bediscussed. The gel 20 has a slow flow rate, or low motility as comparedwith conventional gels and a higher heat capacity as compared withconventional gels. Consequently, the gel 20 will not migrate or flowfrom the pressure points or in response to gravity, thereby retainingmore gel 20 over the desired area for a longer period of time thanconventional gels. Additionally, because of the increased heat capacityof the gel 20, a thermal pack incorporating such a gel retains itsheating and cooling capacity for longer periods of time, thus makingsuch a pad more convenient. The gel 20 of the preferred embodimentincludes a mixture of clay, water and fibrous material. Also, for gelsused in cold pads a substance to lower the freezing point is necessary.Such a substance can include glycol or sodium. Such a gel shouldcontain, by weight, approximately 15% to 30% clay, 0% to 75% water, 1.0%to 10% fibrous material and 0% to 60% of a substance to lower thefreezing point. A mixture of 23.5% clay, 33% glycol, 41% water and 2.5%fibrous material has proven particularly effective. However, variouspercentages of clay, water, fiber and glycol can be combined to providesatisfactory results so long as the resulting gel has a slow ornegligible flow rate.

The preferred clay is Bentonite type clay in fine grain form. However,any suitable clay material can be used. The preferred glycol ispropylene glycol. However, any other suitable substance can be used tolower the freezing point, such as introduction of a salt into the wateremployed. The fibrous material can be in the form of fibers, flakes andshreds of any size. The fibers may be individual fibrils, monofilaments,slivers, ribbons or combined as woven or non-woven or plated or twistedfibers, strands, ribbons or threads. A preferred fibrous material isnylon 66. However, any suitable fibrous material can be used. Thepreferable length of the fibers of the fibrous material ranges from 1/4inch to 1/2 inch. Individual fibers, flakes or shreds may be freelysuspended within the gel or attached to each other, or to a substrate ormultiple substrates which may be freely suspended or attached to one ormore of the walls of the pad. It is the fibrous material that gives thegel its unique property of extremely low or negligible flow.

ACHIEVEMENTS

Several advantages are realized with the introduction of the fibrousmaterial into the gel. A greater percentage of water and/or glycol canbe incorporated into the gel mixture without adversely affecting theflow restrictive properties of the gel. The greater the amount of wateror glycol added to the gel, the greater the heat absorption of the gel.Therefore, the use of the fibers also increases the heat capacity of thegel thereby providing a more efficient gel for use in thermal packs.Additionally, the resultant gel has an extremely low or essentiallynon-existent mobility as compared with conventional gels. Consequently,the gel will not migrate from the pressure points or flow in response togravity, thereby providing for a far more effective resultant thermalpack.

While the gel 20 is essentially non-flowing, it is flexible incombination with the plastic material forming the gel pad and thepressure chamber. In any form of the invention, the thermal packconforms readily to the surface of the patient, no matter how irregularthat surface may be. Thus, application of heat or cold therapy isapplied directly to the area being treated without any substantialinsulative air layer or other insulation reducing the efficiency of thethermal pack.

In the tubular form of the invention as shown in FIG. 3, when thethermal pack is applied about a limb being treated and the pressurechamber is inflated, the thermal pack is held snugly in place. Noadditional fasteners, hooks or other means of holding the thermal packare necessary in this form of the invention, a substantial improvementover all other prior art devices that use fasteners or straps to holdtheir devices in place.

In addition to its utility to hold the tubular form of the invention inplace, the pressure chamber, when employed, forms an effective insulantbetween the ambient atmosphere and the gel, so that the therapeuticvalue of the gel is directed to the patient being treated, and is notlost to the atmosphere. In all other commercial devices, no suchinsulant is used, and therefore a substantial percentage of thetherapeutic value of the devices is lost due to convection andconduction to the surrounding atmosphere or any other object in contactwith the device.

Various features of the invention have been shown and described inconnection with the illustrated embodiments of the invention. However,it must be understood that these particular arrangements merelyillustrate, and that the invention is to be given the fullestinterpretation within the terms of the appended claims.

What is claimed is:
 1. A non-flowing gel for use in thermal packs forhuman treatment, said gel comprising a mixture of materialscomprisingclay, a liquid and a fibrous or flake material; the clay beinga clay substrate in an amount of from about 15% to 30% by weight; theliquid including a glycol and water wherein the water is in an amount offrom about 0% to 75% by weight; and the fibrous or flake material beingof sufficient concentration to impart a negligible flow rate in said geland provide uniform contact between the hot or cold pack with theaffected area, wherein said sufficient concentration is from about 1% to10% by weight; the gel being a semi-rigid, non-flowing, extremelyviscous mixture comprising a colloidal dispersion of a solid with aliquid.
 2. A gel as in claim 1 comprising a salt as an additionalcomponent of said gel for lowering the freezing point of said gel.
 3. Agel as in claim 1 wherein said glycol is propylene glycol.
 4. A gel asin claim 1 wherein said proportion of clay to water to fibrous materialto glycol is preferably 23.5/41/2.5/33 by weight.
 5. A gel as in claim 1wherein said clay substrate is bentonite.
 6. A gel as in claim 1 whereinsaid fibrous or flake material is fibers or shreds.
 7. A gel as in claim1 wherein said fibrous or flake material includes fibers of from 1/4 to1/2 inch in length.
 8. A gel as in claim 1 wherein said fibrous or flakematerial is nylon
 66. 9. A gel as in claim 1 wherein said liquid furtherincludes up to 60% glycol by weight.